Propogate additional compilation data from RoslynCompilationService

* Update CompilationFailedException to include path of file being compiled
* Pass in path being compiled to Rolsyn.
* Adding doc comments for compilation pieces

Fixes #869
In this case the `fileInfo` has the cshtml content and `compilationContent` is the stuff we codegen. We're passing in fileInfo to print out the cshtml content in the event we throw an exception.